Water and other aqueous solutions have been injected into hydrocarbon-fueled engines by various ways and means to provide improved operation of said engines, emphasizing a variety of benefits. In the majority of embodiments water is used to cool and condense the air in the intake air stream. During the compression stroke, water droplets absorb heat produced from prior combustion, preventing pre-detonation and auto-detonation. During the power stroke water subsequently expands to super-heated steam by the burning fuel mixture, increasing the mechanical efficiency of the combustion process. Benefits may also include scavenging and preventing carbon deposits and varnish in the combustion chamber of said engines, resulting in improved engine performance and decreased abrasion on internal engine surfaces. Water injected engines are generally reported to run more smoothly with less misfiring. Because adding humidity lowers combustion temperature by enthalpy, water injected engines, especially spark-fired engines, can be adjusted to run on a leaner air/fuel mixture, thus conserving natural resources. Most significantly, reduction in peak combustion temperature minimizes the formation of oxides of nitrogen and reduces thermal stress on engine components.
Hydrocarbon fuels, while categorized into different types and grades, are typically agglomerates of a variety of hydrocarbon chain structures, some shorter, some longer. While it is recognized that the longer-chained structures produce more BTU's than the shorter ones, they take more time to burn and because of today's high revolution engines, the longer chains only get partially burned in the combustion process and are emitted as carbon and hydrocarbon pollutants.
Restructuring the hydrocarbon molecules into more uniformly shorter chains will result in a more complete combustion with a net improvement in fuel economy, BTU production, emissions reduction and cleanliness of internal engine surfaces. This restructuring can be accomplished by passive catalysis without adversely affecting lubricity or any other resident characteristic of the particular hydrocarbon fuel being modified. While this is especially applicable to liquid fuels, it is also beneficial for gaseous fuels.
For these reasons we propose a dual system of water injection and fuel conditioning working in tandem to produce a synergistic benefit for an internal combustion engine. We will review the prior art and set forth ways and means to achieve superior results.
U.S. Pat. No. 1,777,554 to Ducloux proposes a canister filled with metal catalysts, some of which are radioactive, through which he passes fuel and the canister is attached to the exhaust manifold of an engine. He reports significant improvement of the hydrocarbon fuel, resulting in increased fuel economy and better performance. Unfortunately, he was apparently unaware of the inherent dangers of human exposure to radioactive elements. U.S. Pat. No. 2,136,170 to Luertzing illustrates the effectiveness of passing liquids through a fine mesh or porous homogeneous media. U.S. Pat. No. 2,231,605 to Stephenson, et al. offers an oxidation catalyst heated by the engine cooling system. This invention, like the one by Ducloux, places large volumes of combustible fuel directly attached to an engine, where any fuel leakage would be easily ignited and pose grave danger to anyone in near proximity. U.S. Pat. No. 3,059,910 to Moriya proposes a magnetic approach to fuel conditioning in which he claims that the fuel molecules are ionized to improve engine performance. U.S. Pat. No. 3,383,560 to Ginsburgh offers a de-ionization method having to do with the safe grounding and neutralizing of high voltage electrical charges in liquids that pass through conductive pipe or tubing. U.S. Pat. No. 3,597,668 to Yoshimine describes a device similar to a capacitor through which fuel is passed to give it an electrical charge and, purportedly, give better fuel performance. This invention and the two preceding inventions assert that adding or removing or aligning electrical charges on fuel molecules causes them to behave differently in the combustion process to produce a cleaner burning more efficient fuel. This phenomenon may prove to be beneficial in some cases, but fuel is also subjected to other electrical and magnetic forces as it passes through its uneven pathway to a combustion chamber which could reverse the ionic effect of such inventions. U.S. Pat. No. 3,866,579 to Serruys sets forth a method to spray variable amounts of water and increase airflow to the intake of an engine to achieve lower NOx emissions. His method lacks adequate control means and is capable of leaving excessive amounts of water in an intake path after engine shutdown. U.S. Pat. No. 3,911,871 to Williams, et al. introduced the idea of using a binary logic processor to control a piezoelectric transducer to achieve ultrasonic vaporization of water inside the intake plenum of an engine in a vehicle. Their vapor device would present numerous problems, both in its installation and subsequent maintenance or repair because of its internal placement and its inadequate control parameters. Additionally, its piezoelectric vibrator would be considerably vulnerable to rapid deterioration due to its intermittent exposure to air. U.S. Pat. No. 3,915,669 to Minoza suggests a vaporizer carburetor which uses exhaust heat to vaporize water and gasoline and release them into the intake air of a vehicle engine for smooth, responsive acceleration and to reduce the heat of combustion. His device would require new engineering for almost every different engine. U.S. Pat. No. 4,088,450 to Kosaka proposes a type of hydrogen reformer to separate hydrogen from hydrocarbon fuel as it passes through a series of oxidation catalysts heated by the exhaust of an engine. This method produces a hydrogen-enriched fuel but the end result is a fuel that is less efficient, therefore more costly to use. U.S. Pat. No. 4,476,817 to Lindberg reports that inducing steam through an ultrasonic device into the air stream of a gasoline-fueled vehicle engine reduces NOx emissions significantly, boosts the engine's power and smoothness of operation and prevents pre-detonation normally associated with the use of lower octane fuel than factory recommendations. He also reported adjusting the engine to run on a leaner air/fuel ratio. His device would also require special engineering for application on different engines. U.S. Pat. No. 4,715,325 to Walker sets forth a multi-catalyst fuel processor that is purported to give emissions reduction and fuel economy. Results vary with these types of devices and a closer observation reveals that the fuel has very little actual contact time with the catalysts. U.S. Pat. No. 5,580,359 to Wright and U.S. Pat. No. 6,770,105 to Berlin, et al. both set forth inventions similar to Walker and the results appear to be similar. U.S. Pat. No. 5,167,782 to Marlow offers a combination of electrical charge plus catalyst, but with similar results to the three aforementioned inventions. U.S. Pat. No. 4,960,080 to O'Neill et al. describes a system for the reduction of NOx emissions for a turbo-diesel generator set by means of a steady flow spray nozzle water injector that is switched on at a pre-determined electrical load and switched off as the load demand falls below that same pre-determined value. His device is very limited in scope and effectiveness under varying conditions. U.S. Pat. No. 5,522,349 to Yoshihara et al. sets forth a water injection system that meters a spray of water into each cylinder of a diesel engine, timed synchronously with fuel injectors to achieve a spray pattern that he purports to be optimal in the abatement of NOx emissions. Their method calls for an entire combustion chamber design change to accommodate both the fuel injection and water injection systems. U.S. Pat. No. 5,671,701 to O'Donnell proposes a cold steam vapor unit for a vehicle engine, oil burner, boiler or hot water heater. The device raises many questions, such as absence of means to control water vapor, water movement issues in a moving vehicle, evaporation issues allowing excess water vapor to flow into the intake manifold of a warm engine after shutdown, etc. U.S. Pat. No. 6,170,470 to Clarkson et al. illustrates a water injection system for disposing of water condensate in a gasoline fuel tank by a series of sensors and valves that monitor and maintain an intermittent water injection system. Their system offers no continuity of benefits, but rather is a method for water disposal in rare instances. U.S. Pat. No. 6,414,745 to Hellen et al. describes a pulsating water injection system for a four-stroke diesel engine, synchronous with the intake stroke of each cylinder. They postulate that this is the most efficacious application of water injection for a diesel engine. Their system calls for an entire combustion chamber design change. U.S. Pat. No. 6,289,853 to Walczak et al. sets forth a water injection system for a marine engine, acquiring water for his system from a fresh or salt-water source in which a marine vessel moves. Their primary concern is setting forth a purification process to supply their water injection application. U.S. Pat. No. 4,808,287 to Hark and U.S. Pat. No. 5,464,532 to Nowlin et al. demonstrate effective means of providing a de-mineralized, ultra-pure water supply by passing it through ion exchange media and reverse osmosis systems. Those experienced in the art will recognize the advisability of employing such means. U.S. Pat. No. 6,357,671 to Cewers sets forth a means of ultrasonic vaporization of liquids. Though other references not cited have set forth numerous ways to vaporize liquids ultrasonically, this one is given as an example of a method that could be used to create an aqueous vapor for a water injection system such as the one described in the present embodiment.
As evidenced by these examples, various types of devices have been developed to induce water or other aqueous solutions into the intake air of internal combustion engines. These methods are not only limited because of their inability to precisely detect and provide means for optimal engine operation but also are incapable of metering a continuously optimized volumetric ratio of water in the final fuel/air charge. Spray or steam injection systems also could damage the turbine blades in a turbocharged engine unless injected downstream from the compressor. Injecting hot steam also has a disadvantage in that it doesn't have as much expansion capability in the power stroke as cool vapor has.
In the event that one of the prior art systems did not completely cut off the water supply before engine shutdown, an accumulation of water in the intake manifold or combustion chamber could result in corrosive and/or mechanical damage to internal engine parts on subsequent start-up or over a protracted period of time. Although this problem is generally recognized as critical to the effective operation of a water injection system, none of the prior art adequately demonstrates fail-safe measures to assure minimal humidity in an intake manifold at engine shutdown.
Most of the prior art expresses a concern about using unpurified water in a water injection system. However, only one of them offers a means for the removal of minerals from the water, which produces scale and corrosion. Walczak, et al. is the only one that does incorporate any means of water demineralization and their only reason for doing so is to be able to use seawater in their marine application. Analysis of water in most parts of the world reveals a mineral content that presents a concern for use in an engine.
Direct injection of water into the combustion chamber presents similar challenges to other methods, but complicates broad application of its technique by requiring highly specialized controls and injectors, precision machining and an individualized system for every engine style. Related art systems have not been entirely successful in satisfying engine requirements, largely due to their inability to respond adequately to a wide range of engine operating conditions.
None of the prior art, except for our previous patent, addresses the monitoring of exhaust gas temperature as a means for continuous precision control of NOx reduction by water injection. Since combustion temperature is the major contributor to the production of oxides of nitrogen, it is essential to introduce an improved method for exhaust temperature measurement and control in order to achieve a more effective NOx control. None of the prior art addresses water vapor injection for emissions control at engine idle speed. When an engine is idling, it may have significant demand from electrical or mechanical systems that cause elevated combustion temperatures that account for significant volumes of NOx emissions, which is of particular concern in urban population areas. Similarly, none of the prior art addresses water vapor injection for engine block temperature control, which can be a major problem in heavy traffic conditions and other circumstances that require extended periods of engine idling. Additionally, none of the prior art addresses the challenge of reducing emissions at engine idle speed when the engine is not warm enough to warrant water injection. This is accomplished by a catalytic fuel conditioner that causes hydrocarbon fuels to burn cleaner and more completely. Prior art uses both heated and non-heated catalysts to affect a positive change in fuels. While it is evident that heating a catalyst to its optimum reaction level can work faster with less catalytic material, the non-heated catalysts also affect the fuel, but there must be more exposure to the catalyst to achieve satisfactory results.
None of the prior art expresses the adaptability of a water vapor system to a wide range of engine operating conditions and applications. A number of sensing and metering devices that monitor engine operating parameters will be discussed herein to optimize water vapor usage in said engine and establish water-to-fuel ratios that respond rationally to the variable operating conditions of an engine.
Neither has any of the prior art utilized the monitoring of boost pressure to control water vapor flow into the intake air stream of a turbocharged engine. The monitoring of a sudden rise, fall or absence of boost pressure can be utilized to increase, decrease or stop the flow of water vapor to more precisely respond to engine operating conditions and give better engine performance and emissions reduction capabilities to said engine.
None of the prior art has combined the use of a fuel-processing device with a water injection device for a synergistic emissions elimination strategy. Though not physically connected, the two devices work in separate streams of the combustion process to contribute to the overall reduction of emissions from said engine.
None of the prior art addresses the issue of preventing said water supply from freezing in cold-weather conditions. Though unrelated to the primary function of a water injection device, freezing temperatures could cause clogging and possible rupture of water-containing lines and vessels, thus disabling said water injection system and rendering it useless.
It is evident that, for the reasons stated, none of the prior art has provided a water injection system with adequate means to achieve significant technical or commercial acceptance.